Polishing machine



July 11, 1939. p cox 2,165,616

POLISHING MACHINE Filed July 1, 1937 2 Sheet S-Sheet 1" -53 I L5HTTOENEKS:

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' July 11, 1939. J. P cox 2,165,616

POLISHING MACHINE Filed July 1, 1937' 2 Sheets-Sheet 2 lnllllml PatentedJuly 11, 1939 POLISHING MACHINE John P. Cox, St. Louis, Mo., asslgnor toGeneral Motors Corporation, Detroit, Mich" a corporation of DelawareApplication July 1, 1937, Serial No. 151,426

My invention relates to polishing machines, particularly to machines forsandpaperirig the metal tops of automobile bodies. The invention has forits principal object a machine which will do sandpapering automatically,including the feeding of. the sandpaper across the work engaging member.The invention consists principally in a polishing shoe mounted above thework on a support that swings in a vertical plane and is capable of freetilting movement longitudinally and transversely of the work, togetherwith automatic means for intermittently feeding sandpaper or the likeacross the work engaging member. The invention further consists in thepolishing machine and in the parts and combinations and arrangements ofparts hereinafter described and claimed.

In the accompanying drawings,

Fig. 1 is a front elevation of apolishing machine embodying myinvention,

Fig. 2 is a side elevation,

Fig. 3 is a plan view looking in the directions of the arrows 3-3 inFig. 1,

Fig. 4 is a sectional view on the line 4-4 in Fig. 3, v

Fig. 5 is a sectional view on the line 55 in Fig. 6 is a sectional viewon the line 66 in Fig. 1,

Fig. 7 is a detailed view of the ratchet and pawl mecham'smfor feedingthe sandpaper,

Fig. 8 is a bottom plan view of the work engaging shoe-with the covertherefor removed,

Fig. 9 is a plan view showing the mounting of the polishing machine andthe drive meanstherefor; and

Fig. 10 is aside elevation.

The present operation of polishing or sandpapering the tops ofmetalautomobile bodies requires the services of four workmen, each ofwhom sandpapers one-fourth of the top surface as the body moveslongitudinally along the assembly line.

My invention greatly expedites this polishing operation by mounting theabrasive material on.

hrough holes 8 in bosses 9 projecting from said carriage I. Collars Hion said arms 6 engage the inner faces of the bosses 9 and nuts II on thethreaded outer end portions 12 of said arm-s engage the outer faces ofsaid bosses 9. Thus, the hanger arms 6 are movable in a vertical planeabout the horizontal axis formed by the end portions I of the arms 6.The downward, movement of the hanger arms is limited by stop members 13projecting from the carriage 4.

Said arms 6 converge toward their lower ends ll. Said ends H are bentinto a position approaching the horizontal and to them is secured, as bywelding, a hanger plate l5 having depending plates It in which ismounted a shaft I'l that is disposed longitudinally of the work andassembly line. Plvotally mounted on said shaft I1, preferably with abearing sleeve l8 interposed therebetween, is a hanger block l9 throughwhich extends a shaft 20 that is disposed at right angles to said shaftII, that is, transversely of the work. A bearing sleeve 21 is interposedbetween said block 19 and said shaft 20. The ends of said transverseshaft 20 extend into upstanding side walls 22 of the shoe or workengaging member l and are secured thereto by means of set screws 23 andnuts 24. The shoe proper I can thus pivot about said transverseshaft-.20 in a vertical plane extending longitudinally of the work andsaid hanger block l9 canpivot about said longitudinal shaft ll in avertical plane transverse to the work, so that the shoe as a whole isfreely tilt-' able, substantially universally, with respect to the workand can accommodate itself to curvature of the work, whether the work becurved longitudinally or transversely, or both, as in the case of thetop of the automobile body 3, diagrammatically indicated in thedrawings.

The'bottom'or work engaging portion of the shoe has marginal ribs25which extend generally longitudinally of the work, but have concaveinner faces 26. Extending from rib 25 to rib 25 and over the outer faces21 thereof is a pad 28 of rubber or other-resilient material which issecured to the outer faces of the shoe as by screws Secured to the endsof the shoe I, as by screws 30, are end plates 3| which have upwardlyprojecting portions 32 at one end. Mounted on a roller 33 between thetops of said projecting portions is a roll of sandpaper 34 'or otherabrasive material. Said sandpaper 34 passes under a steady roll 35 thatis rotatably mounted between .the lower portions of the end plateprojections, and over a large guide roll 36 rotatably mounted betweenthe end plates 3|. The portion of the sandpaper 34 engaging the upperportion of said guide roll 38 is engaged by a Steady roll 81 rotat-'ably mounted. between the end plates ii and a steady roll 38 engages thelower portion of the sandpaper 34 .as it leaves said guide roll 38. Theends of said lower steady roll 38. project through slots 88 in the endplates 8| and springs 48 urge said lower steady roll toward the guideroll 38.

pends from one arm 41 of a feed lever (indicated generallyby- 48)pivotally mounted on one end of the feed roll 42. A spring 4s secured tothe other arm 58 of said feed lever 48 and to one end plate 8| urges thelever 48 in a direction to let the pawl 48 slide over one or moreratchet wheel teeth iii to engage one tooth ready for the next feedingmovement. An upwardly projecting contact arm 52 at the end of said feedlever. 48 remote from the pawl .48 has a contact screw 53 projectingtherefrom for engagementwith a contact bar 54 projecting from the hangerplate I8,-said engagement causing swinging of the feed lever 48 torotate the ratchet wheel 48. The operation of this feedmechanism will befur ther described hereinafter.

Secured between the lower portions of the hanger arms Sis a brace 55from which depends a leg 88 to the bent lower portion 81 of which ispivotally mounted a caster wheel 58 which is disposed slightly above thelevel of the bottom of the shoe l. Preferably said leg 51 has atelescoping sleeve portion 89 secured to the leg 58 by a set screw 88 sothat the vertical position of the wheel or roller 88 may be-adjusted.

The drawings diagrammatically illustrate a suitable drive mechanism forthe crane 4a on which the carriage 4 is mounted, including a motor 8 Idrive belts 82, driven gears 88, chains 84, idler gears 85, a cross pin88 secured to the two chains 84, and a connecting rod 81 having one endpivotally mounted on said cross pin 88 and the other end on apin 88projecting from said crane. I

As the automobile body I or other work moves longitudinally along theassembly line (the mechanism therefor not being shown) it will passunder the hanger arms 8, which are in the position shown in Fig. 2 untilthe front end of the work engages the caster wheel 88, slightly raisingthe hanger arms and the shoe and bringing the shoe I into operativeengagement with the top'2 of thework. Preferably the shoe and associatedparts are so balanced that the shoe tilts slightly to present theworking surface of the work. The shoe I will then move back andforthacross the work as the work moves longitudinally, the two movementsbeingrso correlated asto give a thorough sandpapering of all portions ofthe top of the work. Ordinarily, the work will be sprayed with waterduring the sandpapering process. At one end of the travel of the shoeover the transversely curved work, the shoe will be tilted about thelongitudinally extending axis so as to bring the contact screw 53 intoengagement with the contact bar 84 and cause the feed lever to be swungto operate the ratchet wheel 48. By adjusting the position of thecontact screw 88 and looking it in adjusted position bymeans-of a locknut. 88, the'stroke of the feed lever 48 can be changed so as toincrease or decrease the amount of rotation of the feed wheel 48 andhence the amount of sandpaper fed at each stroke. v

. Obviously, the above described machine is fully automatic in itsoperation. 'I'hework shoe is able to conform automatically to work thatis curved longitudinally or transversely orboth and the resilient workpad permits the sandpaper to.

accommodateitself to any slight surface irregularities in the work Thesandpaper is auto--' matically fed at intervalsacross the work pad so asto continuouslybring fresh areas of the sandpaper into engagement withthe work.

The invention is applicable to either wet or dry polishing operationsand to operations using other polishing material than sandpaper.

0bvious1y, numerous changes may be made without departing from theinvention and I do not wish to be limited to the preciseconstructionshown. 1

What I claim is: d

1. Automatic polishing tudinally and transversely curving work movingmechanism for longilongitudinally, comprising a support pivotally Imounted for vertical-:swinging movement above.

the work, a shoe suspended from said support to engage the .work andfreely tiltable longitudinally and transversely of thework, said shoehaving marginal ribs extending lonsitudinallyof they work, a resilientpad extending from rib to rib and secured to the outer facesthereof, asheet.

of polishing material covering said resilient pad, and means forreciprocating said shoe transversely of the work as it moveslongitudinally.-

2. Automatic polishing mechanismfor longitudinally and transverselycurving work moving longitudinally, comprising a support pivotallymounted for vertical swinging movement above the work, a shoe suspendedfrom said support toengage the work and freely tiltable longitudinallyand transversely of the work, said shoe having marginal ribs extendinglongitudinally of the work, a resilient pad extending from rib to riband secured to the-outer faces thereof, a sheet of polishing materialcovering said resilient pad,- means for intermittently feeding saidsheet of polishing material across said resilient pad and means forreciprocating said shoe transversely of the work as it moveslongitudinally.

3. Automatic polishing mechanism for longitudinally and transverselycurving work moving longitudinally, comprising a support pivotallymounted for vertical swinging movement above the work, a shoe suspendedfrom said support to engage the work and freely tiltablelongitudinallyand transversely of the work, said shoe having marginal ribs extendinglongitudinally of the work, a resilient padextending from rib to rib andsecured to the outer faces thereof, a sheet of polishing materialcovering said resilient pad,

means actuated by the tilting of said work shoe .at one end of itsmovement over the work for intermittently feeding said sheet ofpolishing material across said resilient pad and-means for reciprocatingsaid shoe transversely as it moves longitudinally.

4. Automatic polishing mechanism for longitudinally and transverselycurving work moving longitudinally, comprising a carriage mounted on atrack extending transversely of the work some distance thereabove, meansfor reciprocating said of the work carriage along said track, a pair ofhanger arms ing plates depending from the ends of said hanger plate, ashaft mounted in said mounting plates, a hanger block pivotally mountedon said shaft, a shaft pivotally mounted in said hanger block at rightangles to said first shaft, a work shoe having upstanding ribs spacedfrom the sides of said hanger block and secured to said transverseshaft, said shoe having depending ribs on its lower or work faceextending substantially longitudinally of the work, a resilient padmounted over said ribs, a sheet of abrasive material extending across,said resilient pad and supporting and feed means for said abrasivematerial.

5. Automatic polishing mechanism for longitudinally and transverselycurving work moving longitudinally, comprising a carriage mounted on atrack extending transversely of the work some distance thereabove, meansfor reciprocating said carriage along said track, a pair of hanger armspivotally secured to said carriage for vertical swinging movement, saidarms converging downwardly, a hanger plate secured to the approximatelyhorizontal lower end portions of said arms and disposed longitudinallyof the work, mounting plates depending from the ends of said hangerplate, a shaft mounted in said mounting plates, a hanger block pivotallymounted on said shaft, a shaft pivotally mounted in said hanger block atright angles to said first shaft, a work shoe having upstanding ribsspaced from the sides of said hanger block and secured to saidtransverse shaft, said shoe having depending ribs on its lower or workface extending substantially longitudinally of the work, a resilient padmounted over said ribs, a sheet of abrasive material extending acrosssaid resilient pad, supporting and feed means for said abrasive materialincluding a feed roll having a ratchet wheel secured thereto, a feedlever pivotally mounted on the end of said feed roll adjacent to saidratchet wheel, a feed pawl depending from one arm of said feed lever, aretracting spring for said feed lever, a contact arm projecting fromsaid feed lever at the end remote from said pawl, a contact screwprojecting upwardly from said contact arm and a contact bar projectingfrom said hanger plate in position to be engaged by said contact screwwhen the shoe is tilted at one end of its movement over the transverselycurving work.

6. Automatic polishing mechanism for longitudinally and transverselycurving work moving longitudinally, comprising a carriage mounted on atrack extending transversely of the work some distance thereabove, meansforreciprocating said carriage along said track, a pair of hanger armspivotally secured to said carriage for vertical swinging movement, saidarms converging downwardly, stops for limiting the downward movement ofsaid arms, a hanger plate secured to the approximately horizontal lowerend portions of said arms and disposed longitudinally of the work,mounting plates depending from the ends of said hanger plate, a shaftmounted in said mounting plates, a hanger block pivotally mounted onsaid shaft, a shaft pivotally mounted in said hanger block at rightangles to said first shaft, a work shoe having upstanding ribs spacedfrom the sides of said hanger block and secured to said transverseshaft, said shoe having depending ribs on its lower or work faceextending substantially longitudinally of the work, a resilient padmounted over said ribs, a'sheet of abrasive material extending acrosssaid resilient pad, and supporting and feedmeans for said abrasivematerial.

'7. Automatic polishing mechanism for longitudinally and transverselycurving work moving longitudinally, comprising a carriage mounted on atrack extending transversely of the work some,

distance thereabove, means for reciprocating said carriage along saidtrack, a pair of hanger arms pivotally secured to said carriage forvertical swinging movement, said arms converging downwardly, a hangerplate-secured to the approximately horizontal lower end portions of saidarms and disposed longitudinally of the work, mounting plates dependingfrom the ends of said hanger plate, a shaft mounted in said mountingplates, a hanger block pivotally mounted on said shaft, a shaftpivotallymounted in said hanger block at right angles to said first shaft, a workshoe having upstanding ribs spaced from the sides of said hanger blockand secured to said transverse shaft, said shoe having depending ribs onits lower or work face extending substantially longitudinally of thework, a resilient pad mounted on said ribs, a sheet of abrasive materialextending across said resilient pad, a depending leg having its upperend mounted between the lower end portions of said converging arms, acaster wheel mounted at the bottom of said legs to be engaged by thework in advance of said shoe, thereby raising the shoe into operativeposition, and feed means for said abrasive material actuated by thetilting of the shoe at one end of its movement over the transverselycurving work.

8. Automatic polishing mechanism for longitudinally and transverselycurving work moving longitudnally, comprising a carriage mounted on atrack extending transversely of the work some distance thereabove, meansfor reciprocating said carriage along said track, a pair of hanger armspivotally secured to said carriage for vertical swinging movement, saidarms converging downwardly, a hanger plate secured to the approximatelyhorizontal 'lower end portions of said arms and disposed longitudinallyof the work, mounting plates depending from the ends of said hangerplate, a shaft mounted in said mounting plates, a hanger block pivotallymounted on said shaft, a shaft pivotally mounted in said hanger block atright angles to said first shaft, a work shoe having upstanding ribsspaced from the sides of said hanger block-and secured to saidtransverse shaft, said shoe having depending ribs on its lower or workface extending substantially longitudinally of the work, a resilient padmounted on said ribs, a sheet of abrasive material extending across saidresilient pad, a depending leg having its upper end mounted between thelower end portions of said converging arms, a caster wheel mounted atthe bottom of said legs to be engaged by the work in advance of saidshoe, thereby raising the shoe into operative position, means foradjusting the vertical position of said caster wheel, and feed means forsaid abrasive material actuated by the tilting of the shoe at one end ofits movement over the transversely curving work.

9. Automatic polishing mechanism for longitudinally and transverselycurving work moving longitudinally, comprising a carriage mounted on atrack extending transversely of the work some distance thereabove, meansfor reciprocating said carriage along said track, a pair of hanger armspivotally secured to said carriage for vertical swinging movement, saidarms converging downwardly. a-hanger plate secured to the approximatelyhorizontal lower end portions of'said arms and disposed longitudinallyof the work, mounting plates depending-from the-ends of said hangerplate. a shaft mounted in said mounting plates and disposedlongitudinally with respect to the work, a hanger block pivotallymounted on said shaft, a shaft pivotally mounted in said hanger blocktransversely to said first shaft and to the work, a work shoe havingupstanding ribs spaced from the sides of said hanger block and securedto said transverse shaft, said shoe having depending ribs on its loweror work face extending substantially longitudinally of the work, aresilient pad mounted over said ribs, end plates secured to the ends ofsaid shoe and having upstanding supports at one end, a roll of abrasivematerial rotatably mounted in said supports, said abrasive materialbeing directed across said resilient pad, feed means for said abrasivematerial including a feed roll having a ratchet wheel secured thereto, afeed lever pivotally mounted on the end of said feed roll adiacent tosaid ratchet wheel. a feed pawl depending from one arm of said feedlever, a retracting spring for said feed lever. a contact arm projectingfrom said feed lever at the end remote'from said pawl, a'contact screwprojecting upwardly from said contact arm and a contactbar projectingfrom said hanger plate in position to be engaged by said contact screwwhen the shoe is tilted at one end 'of its movement over thetransversely curving work.

JOHN P. cox.

